When a provisional pattern layout of a memory cell array is determined in the process of manufacturing, for example, a semiconductor memory device, the pattern layout is used and an optical proximity correction (OPC), etc., are executed to determine a mask pattern. A hard mask is manufactured based on the mask pattern. An MRAM having a magnetic tunnel junction (MTJ) element is also manufactured by a similar process.
Also, a memory cell array region generally has a plurality of patterns corresponding to memory cells at regular intervals, and a sufficient number of dummy cells to stabilize a critical dimension (CD) of the memory cells are arranged in an end portion of the memory cell array region.